Eleocharis. CLX. CYPERACE^. 569 



Tribe 3. SCIRPE.E.— Flowers ^ . Glumes of the spikelet inabricated all 



around. Perigynium none, or setaceous. 



6. ELEOCHARIS. R.Br. 



&/•. eXof J a marsh, ;^;aipco, to rejoice ; plants delighting in marshy grounds. 



Spikes terete ; bristles of the perigynium mostly 6 (3 — 12), rigid, 

 persistent ; styles 2 — 3-cleft, articulated to the ovary ; achenium 

 crowned with a tubercle which is the persistent, bulbous base of the 

 style. — Stem simple^ leafless. Spike solitary^ terminal. 



§ Spikes cylindrical.! length more than three times the diameter. 



1. E. EauisEToiDEs. Torr. (Scirpus. Elliott.') Horse-tail Rush. 



St. about 2f high, papillose, terete, 2 — 3" diam., with about 30 joints, pro- 

 duced by internal, transverse partitions; sheath radical, obtuse, membranous; 

 spike oblong-cylindrical, about 1' in length, acute and slightly contracted at 

 case ; glumes roimdish-ovate, cartilaginous, obtuse ; bristles G, as long as the 

 achenium; stii. 3-cleft; ach. brown, shining. — Bogs, Cumberland, R. I., Olncij ! 

 Del. to Ga. It strikingly resembles Equisetum hyemale. 



2. E. auADRANGaLATA. R. Br. (Scirpus. Mlchx.) 



St. 2 — 4f high, acutely and unequally quadrangular, the broadest side 

 convex, the others concave ; sheaths radical, purplish ; spike 1' or more in length ; 

 glumes roundish-ovate, obtuse, coriaceous ; bristles 6 ; ach. obovate, of a dull 

 white. — Penn., Md., Dr. Robbins, to Ga. and La. In swamps and inundated 

 banks. 



3. E. RoEBiNsii. Oakes. Rabbins' Chib Rush. 



Sts. clustered, 9 — 25' high, rigid, sharply triangular, pale green, several 

 of them fruitless ; s/ieath truncate ; spike 3 — 12" long, scarcely thicker than the 

 stem, placed 2 — 5" below its apex ! glumes 3 — 9, linear-lanceolate, acute, finally 

 brownish ; bristles 6, twice longer than the achenium; ach. 1" long, pale brown ; 

 tubercle closely sessile. — Ponds and ditches, N. H. and Mass., Rickard! Very 

 distinct. In water a part of the stems are floating and as fine as hairs. July. 



§ § Spike ovate, length less than three times the diameter. * Stems terete. 



4. E. PALusTRis. R. Br. (Scirpus. Linn.) Marsh Club Rush. 



St. leafless, round, inflated ; spilcelels smooth and shining, lance-oblong, 

 acute, often oblique, terminal ; glumes subacute, the lower ones larger, some- 

 times empty. — Low grounds, U. S. and Brit. Am. Root creeping. Stems nu- 

 merous, 1 — 2if high, each with an obtuse sheath at the base. Achenium round- 

 ish-obovoid, rugose, punctate, surrounded with 3 or 4 scabrous bristles, and 

 crowned with a tubercle. July. 



5. E. OBTusA. Schultes. (Scirpus obtusus. Willd. Scirpus capitatus. TF«/<.) 

 St. sulcate, subterete, 6 — 15' high ; spikelet ovoid, very obtuse, often near- 

 ly globose ; glivmcs round, dark brown, with whitish margins ; ach. obovate, 

 compressed, smooth, brown, invested with 6 setae as long as the glumes. — Shal- 

 low waters. Can. and U. S., common. July. 



6. E. TUBERCULOSA. R. Br. (Scirpus. Michx.) 



St. columnar, striate, 12' high, leafless, sheathed at base ; spikelet ovate- 

 lanceolate; glumes very obtuse, loose ; acA. .somewhat triquetrous, smaller than 

 the sagittate" tubercle with which it is crowned ; bristles 6, as long as the tuber- 

 cle. — Sandy swamps, N. Eng. ! to Flor. Remarkable for its large tubercle. Jl. 

 * * Stems compressed or angular. 



7. E. oLivACEA. Torr. 



Sts. Ccespitose, 2 — 1' high, slender, compressed, sulcate, soft ; spike ovate, 

 acutish 2 — 3" long, 20 — 30-tiowered ; glumes ovate, obtuse, reddish-brown, with 

 scarious edges and a green midvein, the lowest largest ; bristles G ; .<;/(/. 2-cleft ; 

 ach. broadly obovate, smooth, of a dull, blackish-olive color when ripe. — Sands, 

 generally partly submersed. Providence, R. I., Olney! Mass. to N. J. 



8. E. INTERMEDIA. Schultes. (Scirpus. Muhl.) "Purf Club Rush. 



St. ccespitose, setaceous, difi'use, compressed, furrowed, hard and wiry, 



